Machine body equivalent connecting rod model establishment method and multi-leg coordination control method

Abstract

The invention belongs to the field of robot control, and particularly relates to a multi-leg coordination control method of a hexapod robot. The method comprises the following steps: equating the machine body of the hexapod robot into six connecting rods, and disposing two mutually vertical virtual joints at one end of a geometric center of the machine body; for the connected virtual connecting rods, the axial line of one virtual joint is always along the gravity direction, calling the virtual joint as a first virtual joint; connecting the other virtual joint to the first virtual joint, the axial line of which is always vertical to the gravity direction, calling the virtual joint as a second virtual joint, and vertically connecting the virtual connecting rods with the second virtual joint;constructing a first kinematic coordinate system by using a D-H modelling method according to the coordinate change rule, and solving a tail end coordinate vector of each leg according to a homogeneous transformation matrix by using the forward kinematics; solving a rotation angle of each joint according to the solution of the inverse kinematics; and establishing a joint rotation angle solver. Byadoption of the method provided by the invention, the legs can be efficiently coordinated, and the machine body posture is dynamically adjusted when the robot walks in all directions.

Description

Technical field [0001] The invention belongs to the field of robot control, and specifically relates to a method for establishing an equivalent connecting rod model of a fuselage and a method for multi-leg coordinated control. Background technique [0002] Since the 1980s, many research institutions and universities at home and abroad have successfully developed many high-performance hexapod robots, such as Genghis, Asterisk and Ariel, and discussed related basic theories in depth. Hexapod robots can be realized while walking. The posture adjustment of the fuselage is the basic requirement for the practical application of the hexapod robot in the field environment, and it is also the key to give full play to its potential. The core of the hexapod robot lies in its coordinated control. Some recent studies have considered the posture adjustment in the robot's stroke, and partially solved the problem of the lack of effective foot trajectory and body motion planning methods. Li Manho...

AI Technical Summary

Problems solved by technology

The core of a hexapod robot lies in its coordinated control. Some recent studies have considered the attitude adjustment during the robot stroke, which partially solved the problem of lack of effective foot trajectory and body motion planning methods. Li Manhong and Zhang Xiaojun used motion The relativity of the body posture planning problem is transformed into the foot trajectory planning problem of each supporting foot, which simplifies the inverse solution of the parallel mechanism, but introduces the coupling between the foot trajectory planning and the body motion planning. If no decoupling , the foot end trajectory planned in the body coordinate system will be distorted in the reference coordinate system, the decoupling process is to put the foot end trajectory planning into the reference coordinate system, and then transform it to the body coordinate system, which will give the foot end trajectory planning It is troublesome because it is impossible to directly plan the foot end trajectory in the body coordinate system. The foot end trajectory planning in the reference coordinate system has many limitations. For example, most of the foot end trajectory planning research is carried out in the body coordinate system. However, using the reference coordinate system to plan the trajectory of the foot end is not convenient for applying previous research results; the conversion method from the reference coordinate system to the body coordinate system proposed by Li Manhong et al. is only applicable when the ground level or inclination angle is known. The unknown ground inclination angle limits the field adaptability of the hexapod robot. B. Veekshan Sree Sesha Sai et al. based on the dual PI control system of the roll and pitch axes, proposed that the hexapod robot maintain the fuselage on the slope of the inclination position. The horizontal closed-loop algorithm has been successfully tested on the inclined surface on the Amrita Hexapod Robot (AHR). But this algorithm is only suitable for the case where the feet are symmetrical about the geometric center of the body, and the hexapod robot is traveling When the feet are often asymmetrical, this algorithm will cause some of the feet to fail to touch the ground, reducing the stability of the robot and increasing the force on the remaining supporting feet; at the same time, this algorithm can only be used for closed-loop control , the open-loop adjustment of the fuselage attitude cannot be realized

Images